Engine Overspeed

[digger]

If you read carefully, he said he was doing pulls, he downshifted to 3rd at 60mph, which is fine, and climbed up and not paid attention to shift around the 8600 limiter and the engine blew, that said, it seems it was going to blow anyways, as said above, one visit to 8600 won't destroy an engine, it was either a constant over-reving that wore the engine down up to the point it couldn't take anymore or a mapping issue that caused severe detonation blowing it out. Regardless, sad about your engine OP

could also be some other mechanical failure due to a component quality or even assembly issue

[Apex_80]

If you read carefully, he said he was doing pulls, he downshifted to 3rd at 60mph, which is fine, and climbed up and not paid attention to shift around the 8600 limiter and the engine blew, that said, it seems it was going to blow anyways, as said above, one visit to 8600 won't destroy an engine, it was either a constant over-reving that wore the engine down up to the point it couldn't take anymore or a mapping issue that caused severe detonation blowing it out. Regardless, sad about your engine OP

Yea I see what he was saying but to me if you're still under your decided rev limiter than it was not an overrev. Unless for some strange reason the limiter did not catch it and it went past 8600.

[SliM3]

Yea I see what he was saying but to me if you're still under your decided rev limiter than it was not an overrev. Unless for some strange reason the limiter did not catch it and it went past 8600.

Here's where I think I messed up; I have dyno mode selected (02 rolling road) in the tune and had that rev limiter set to 9000, so when it came time to tune the cams I'd be able to find peak without worrying about fuel cut. DSC just so happened to be disabled because I didn't reset a pressure sensor, so I believe this condition enabled the dyno modes 9k rev limiter instead of the 8600 limiter that's programmed under normal conditions.

From what I could pull out the engine with a magnet, it looks like the alignment pins failed and that was it for the cap. It is in pieces, split just off center & I know CARR bolts wouldn't be the first thing to go when stretched properly. So I (tentatively) attribute this to cap failure @ +9k, on a set of rods that weren't Carillo's 😉

[digger]

the dowel is for alignment only, the cap and rod are held together by preload and resulting friction. There are methods to improve transverse shear capability so you aren't relying on friction. What rods are these?

[SliM3]

the dowel is for alignment only, the cap and rod are held together by preload and resulting friction. There are methods to improve transverse shear capability so you aren't relying on friction. What rods are these?

They are Integrated Engineering rods. The 1.52 rod to stroke ratio doesn't necessarily play nice @ high engine speeds either, as it moves the load further from the center line closer to the junction. I'm not blaming the rods because they did hold on to +9k! I'd just say that Carillo's or even Pauters would've survived without needing a teardown, but in all reality I'm not trying to run that high-strung.




On a side note for those interested in validation, 440cc injectors running E85, held 12:1 AFR so definitely plenty of duty cycle; Whereas the stockers hit close to 90% DC on pump gas once you get up around 8500.

[kaiv]

I've seen a stock motor hit 9k through a botched downshift on the track. It's still perfectly healthy some 3 years later. If you talked to track guys (and if they were willing to admit it) or had a way to log I'm sure you'd find a lot of these motors have seen some revs at a point or another. I'm more inclined to think it was an issue with the assembly or components personally.

[digger]

I've seen a stock motor hit 9k through a botched downshift on the track. It's still perfectly healthy some 3 years later. If you talked to track guys (and if they were willing to admit it) or had a way to log I'm sure you'd find a lot of these motors have seen some revs at a point or another. I'm more inclined to think it was an issue with the assembly or components personally.

i'll second that, would want to rule out a process /assembly issue for sure could happen with any rod.

SliM3 show us more carnage pics? you can often tell if a bolt came loose / failed often